The Light List indicates that a light has a nominal range of 20 miles and is 52 feet high. If the visibility is 12.0 miles and your height of eye is 20 feet, at what approximate distance will you sight the light?

Correct Answer: Option C — 13.7 miles

Calculate the geographic range by adding the distance of the light (d = 1.17 * sqrt(height)) to the observer's distance (d = 1.17 * sqrt(height)). With a 52-foot light and 20-foot eye, the geographic range is 8.4 + 5.2 = 13.6 miles. Since 13.6 is less than the 20-mile nominal range, 13.6-13.7 is the sighting distance.